Idea needing some thought

I had an idea the other day about riding gravity into the smaller 5th dimension and then jumping out of it back to normal space time as a way of FTL travel. Now i don't know if this is the right place to ask questions like this but what would the feasibility/problems be like for such an idea and how would your think it could be done...

According to what i have read in string theory gravity appears to leak into higher dimensions, if a spaceship could also leak into this higher dimension (5th) then travel in this dimension and jump out of it at a desired location it would avoid the limit of light speed.

I know such theories of hyperspace might be similar I'm wondering if theoretically one could jump into the 5th dimension (which would be a great deal smaller than the 4d universe according to some theories i've read) travel at sublight in the 5th dimension and then jump out to wherever it is they desired. Mapping the entire universe onto a milimeter or smaller sized 5th dimension reducing the ship to something of this scale and then jumping back out again.

This is an idea i had for a book, it would allow almost instant travel throughout the universe. What do you think?

You're misunderstanding what a "smaller dimension" entails. If you "leaked yourself" into that 5th dimension (whose entire diameter is less than that of an atom), you could cross it and emerge again - but you would have moved less than the diameter of an atom.

Is it plausible that the idea of hyperspace can be seen as a shrinking on the universe on a higher dimensional plane, so that if one were to enter the dimension by whatever means they could travel across the universe in a fraction of the time it would take normally.

I read somewhere that the smaller you get the more dimensions are available to you...

"The first three dimensions, length, height and width, are familiar to all of us. The fourth dimension is time. But what are the extra dimensions? "Imagine a tightrope stretched between skyscrapers," says Hewett. "If you are watching an acrobat walk across it — the tightrope looks like a line. But if you are watching an ant walk on the tightrope, you can see that the tightrope is thick and round." The extra dimensions postulated in string theory are like the tightrope with an ant on it; they are too small to see unless you get really, really close. "
From: http://www.physorg.com/news10682.html

Remember this is for a novel so i'm trying to come up with something that has some sort of basis in proper string theory and doesn't use the same old wormholes or folding space ideas.

"Imagine a tightrope stretched between skyscrapers," says Hewett. "If you are watching an acrobat walk across it — the tightrope looks like a line. But if you are watching an ant walk on the tightrope, you can see that the tightrope is thick and round." The extra dimensions postulated in string theory are like the tightrope with an ant on it; they are too small to see unless you get really, really close. "

Yes, the tightrope is actually a great way of visualizing it. Alas, it's also a great way of invalidating your idea. Your idea, transposed onto the tightrope would mean that the tightrope walker could shrink himself down so small that he experiences the tightrope as two dimensional - with length and circumference.

But your idea then supposes that if he traversed the short dimesnion (i.e. circles the tightrope's circumference), he should, for some reason, emerge at the far end of the rope.